Avoid mir in implicit_return

Author: camsteffen

clippy_lints/src/implicit_return.rs

@@ -1,4 +1,4 @@
-use crate::utils::{fn_has_unsatisfiable_preds, match_panic_def_id, snippet_opt, span_lint_and_then};
+use crate::utils::{match_panic_def_id, snippet_opt, span_lint_and_then};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
@@ -133,19 +133,13 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitReturn {
         span: Span,
         _: HirId,
     ) {
-        let def_id = cx.tcx.hir().body_owner_def_id(body.id());
-
-        // Building MIR for `fn`s with unsatisfiable preds results in ICE.
-        if fn_has_unsatisfiable_preds(cx, def_id.to_def_id()) {
+        if span.from_expansion() {
             return;
         }
-
-        let mir = cx.tcx.optimized_mir(def_id.to_def_id());
-
-        // checking return type through MIR, HIR is not able to determine inferred closure return types
-        // make sure it's not a macro
-        if !mir.return_ty().is_unit() && !span.from_expansion() {
-            expr_match(cx, &body.value);
+        let body = cx.tcx.hir().body(body.id());
+        if cx.typeck_results().expr_ty(&body.value).is_unit() {
+            return;
         }
+        expr_match(cx, &body.value);
     }
 }